<!DOCTYPE html><html lang="[&quot;zh-Hans&quot;,&quot;zh-CN&quot;,&quot;default&quot;]"><head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1"><meta name="description" content="HTTP的持久化连接和管线化"><meta name="keywords" content="HTTP"><meta name="author" content="wenmu"><meta name="copyright" content="wenmu"><title>HTTP的持久化连接和管线化 | 温木的博客</title><link rel="shortcut icon" href="/melody-favicon.ico"><link rel="stylesheet" href="/css/index.css?version=1.6.1"><link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/font-awesome@latest/css/font-awesome.min.css?version=1.6.1"><link rel="dns-prefetch" href="https://cdn.staticfile.org"><link rel="dns-prefetch" href="https://cdn.bootcss.com"><link rel="dns-prefetch" href="https://creativecommons.org"><link rel="dns-prefetch" href="http://ta.qq.com"><script>(function() {
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} </script><meta name="generator" content="Hexo 4.2.0"></head><body><i class="fa fa-arrow-right" id="toggle-sidebar" aria-hidden="true"></i><div id="sidebar"><div class="toggle-sidebar-info text-center"><span data-toggle="切换文章详情">切换站点概览</span><hr></div><div class="sidebar-toc"><div class="sidebar-toc__title">目录</div><div class="sidebar-toc__progress"><span class="progress-notice">你已经读了</span><span class="progress-num">0</span><span class="progress-percentage">%</span><div class="sidebar-toc__progress-bar"></div></div><div class="sidebar-toc__content"><ol class="toc"><li class="toc-item toc-level-3"><a class="toc-link" href="#什么是持久化连接"><span class="toc-number">1.</span> <span class="toc-text">什么是持久化连接</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#为什么要用长连接"><span class="toc-number">2.</span> <span class="toc-text">为什么要用长连接</span></a></li></ol></div></div><div class="author-info hide"><div class="author-info__avatar text-center"><img src="https://i.loli.net/2020/02/27/xwaBoOj158MfNyq.jpg"></div><div class="author-info__name text-center">wenmu</div><div class="author-info__description text-center">记录一些在工作中或学习新知识时学到的一些知识点；正所谓好记性不如一个烂笔头，温故而知新！</div><hr><div class="author-info-articles"><a class="author-info-articles__archives article-meta" href="/archives"><span class="pull-left">文章</span><span class="pull-right">115</span></a><a class="author-info-articles__tags article-meta" href="/tags"><span class="pull-left">标签</span><span class="pull-right">52</span></a><a class="author-info-articles__categories article-meta" href="/categories"><span class="pull-left">分类</span><span class="pull-right">30</span></a></div></div></div><div id="content-outer"><div class="no-bg" id="top-container"><div id="page-header"><span class="pull-left"> <a id="site-name" href="/">温木的博客</a></span><i class="fa fa-bars toggle-menu pull-right" aria-hidden="true"></i><span class="pull-right menus"><a class="site-page" href="/">首页</a><a class="site-page" href="/archives">文章</a><a class="site-page" href="/tags">标签</a><a class="site-page" href="/categories">分类</a></span></div><div id="post-info"><div id="post-title">HTTP的持久化连接和管线化</div><div id="post-meta"><time class="post-meta__date"><i class="fa fa-calendar" aria-hidden="true"></i> 2020-01-09</time><span class="post-meta__separator">|</span><i class="fa fa-inbox post-meta__icon" aria-hidden="true"></i><a class="post-meta__categories" href="/categories/HTTP/">HTTP</a></div></div></div><div class="layout" id="content-inner"><article id="post"><div class="article-container" id="post-content"><h3 id="什么是持久化连接"><a href="#什么是持久化连接" class="headerlink" title="什么是持久化连接"></a>什么是持久化连接</h3><p>所谓持久化连接(长连接)，就是当 http 建立了连接通信后，TCP 连接不断开，下次请求可以直接使用，无需再创建 TCP 连接。<br>持久接的特点是，只要任意一端没有明确提出断开连接，则保持 TCP 连接状态。</p>
<a id="more"></a>

<h3 id="为什么要用长连接"><a href="#为什么要用长连接" class="headerlink" title="为什么要用长连接"></a>为什么要用长连接</h3><p>发出请求时需要创建 TCP 连接，但是创建 TCP 连接需要三次握手；<br>因为页面上只有一两个请求的页面很少，如果每个请求都创建自己的 TCP 连接，每个都要重复的建立和断开，这非常的浪费服务端资源，并且请求响应时间也相对较长。<br>在这种情况下，长连接就应运而生了。<br>HTTP/1.1 中默认都是长连接，TCP 连接创建后，后面的请求都会使用已创建的 TCP 连接。从而减轻服务端的负载，提高响应时间，加快页面显示速度。</p>
<p>###管线化<br>所谓管线化，就是不用等待响应可直接发送下一个请求。<br>持久连接使得多数请求以管线化（ pipelining）方式发送成为可能。从前发送请求后需等待并收到响应， 才能发送下一个请求。管线化技术出现后，不用等待响应可直接发送下一个请求。<br>这样就能够做到同时并行发送多个请求， 而不需要一个接一个地等待响应了。</p>
<ul>
<li>管线化机制通过持久化连接完成，仅 HTTP/1.1 支持此技术</li>
<li>只有 GET 和 HEAD 请求可以进行管线化，而 POST 则有所限制</li>
<li>初次建立连接时不应启动管线化机制，因为对方(服务器)不一定支持 HTTP/1.1 版本</li>
<li>管线化不会影响响应到来的顺序，响应的返回顺序并未发生改变</li>
<li>HTTP/1.1 要求服务器端支持管线化，但并不要求服务器端也对响应进行管线化处理，只是要求管线化的请求不失败即可。</li>
<li>由于上面提到的服务端问题，开启管线化很可能并不会带来大幅度的性能提升，而且很多服务器端和代理程序对管线化的支持并不友好，因此现代浏览器如 Chrome 和 Firefox 默认并未开启管线化支持。</li>
</ul>
</div></article><div class="post-copyright"><div class="post-copyright__author"><span class="post-copyright-meta">文章作者: </span><span class="post-copyright-info"><a href="mailto:undefined">wenmu</a></span></div><div class="post-copyright__type"><span class="post-copyright-meta">文章链接: </span><span class="post-copyright-info"><a href="http://blog.wangpengpeng.site/2020/01/09/HTTP%E7%9A%84%E6%8C%81%E4%B9%85%E5%8C%96%E8%BF%9E%E6%8E%A5%E5%92%8C%E7%AE%A1%E7%BA%BF%E5%8C%96/">http://blog.wangpengpeng.site/2020/01/09/HTTP%E7%9A%84%E6%8C%81%E4%B9%85%E5%8C%96%E8%BF%9E%E6%8E%A5%E5%92%8C%E7%AE%A1%E7%BA%BF%E5%8C%96/</a></span></div><div class="post-copyright__notice"><span class="post-copyright-meta">版权声明: </span><span class="post-copyright-info">本博客所有文章除特别声明外，均采用 <a href="https://creativecommons.org/licenses/by-nc-sa/4.0/" target="_blank" rel="noopener">CC BY-NC-SA 4.0</a> 许可协议。转载请注明来自 <a href="http://blog.wangpengpeng.site">温木的博客</a>！</span></div></div><div class="post-meta__tag-list"><a class="post-meta__tags" href="/tags/HTTP/">HTTP</a></div><div class="post-qr-code"><div class="post-qr-code-item"><img class="post-qr-code__img" src="https://i.loli.net/2020/02/27/hOBzIxFDJMCrmtN.jpg"><div class="post-qr-code__desc">微信打赏</div></div></div><nav id="pagination"><div class="prev-post pull-left"><a href="/2020/01/09/Append%E5%92%8CAppendChild%E7%9A%84%E5%8C%BA%E5%88%AB/"><i class="fa fa-chevron-left">  </i><span>javascript原型链容易混淆的相关知识</span></a></div><div class="next-post pull-right"><a href="/2020/01/09/JavaScript%E5%BC%82%E6%AD%A5%E5%8A%A0%E8%BD%BD%E7%9A%84%E4%B8%89%E7%A7%8D%E6%96%B9%E5%BC%8F/"><span>JavaScript异步加载的三种方式</span><i class="fa fa-chevron-right"></i></a></div></nav><div id="vcomment"></div><script src="https://cdn1.lncld.net/static/js/3.0.4/av-min.js"></script><script src="https://cdn.jsdelivr.net/npm/valine/dist/Valine.min.js"></script><script>var notify = 'false' == true ? true : false;
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